Directory assistance dialog with configuration switches to switch from automated speech recognition to operator-assisted dialog

ABSTRACT

A method of providing a caller with a directory assistance dialog. The dialog is configurable, at any level of the dialog, from an automated speech recognition (ASR) dialog to an operator-assisted (OP) dialog. The dialog is handed off to an operator if any level of the speech recognition dialog fails. Also, a configuration switch may be set to cause the dialog to be handed off to an operator even if a response at some level of the ASR dialog is successfully recognized.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation from U.S. patent application Ser. No.10/927,922, filed on Aug. 27, 2004 now U.S. Pat. No. 7,050,560 by JohnM. Martin et al. and entitled “Directory Assistance Dialog withConfiguration Switches to Switch from Automated Speech Recognition toOperator-Assisted Dialog,” which is a continuation from U.S. patentapplication Ser. No. 10/120,809, filed on Apr. 11, 2002 by John M.Martin et al. and entitled “Directory Assistance Dialog withConfiguration Switches to Switch from Automated Speech Recognition toOperator-Assisted Dialog,” now U.S. Pat. No. 6,792,096, the contents ofwhich are hereby incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

The following invention relates to telecommunications systems, and moreparticularly to automating directory assistance using speechrecognition.

BACKGROUND OF THE INVENTION

An early step toward automation of directory assistance was the use ofstore and forward technology to assist live operators. The caller wasasked for a locality by a pre-recorded prompt. The store and forwardsystem stored a compressed version of the caller's response to theprompt, and brought a live operator onto the line. The operator heard acompressed version of the response and then completed the remainingdialog with the caller to provide a unique telephone number

More recently another form of automated directory assistance has beendeveloped, which uses automated speech recognition technology torecognize a locality from the caller's response to a prompt. In atypical system, if the speech recognition is successful, the system asksfor the listing, puts an operator on the line, populates the operator'sworkstation display with the recognized locality, and plays a recordedcompressed version of the caller's response to the listing question. Theoperator then conducts the remaining dialog.

Systems have been developed that attempt to carry the speech recognitionthrough the entire dialog of locality, database listing, clarification,and disambiguation. Recognition success rates have increased but are not100%. The conventional approach to improving the success rate is to“tune” the system by recording callers' responses and using them toexpand the speech recognition capability.

The likelihood of failed speech recognition requires that the system becapable of defaulting to an operator. The conventional approach is toautomatically hand off the call to a live operator after a failedattempt at speech recognition. This aspect of automation is described inU.S. Pat. Nos. 4,979,206, 5,479,488, and 5,987,414.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the basic dialog of a method of controlling the levelof directory assistance automation, using configuration switches inaccordance with one aspect of the invention.

FIG. 2 illustrates an example of a sub-dialog for callers who indicatethat they desire a residential listing in response to Question 3 of FIG.1.

FIG. 3 illustrates an example of a sub-dialog for the give-out processof FIG. 1.

FIG. 4 illustrates an example of a sub-dialog for the reverse directoryassistance process of FIG. 1.

FIG. 5 illustrates an example of a sub-dialog for the disambiguationprocess of FIG. 1 or FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

The method described herein provides a path of service evolution fromoperator-assisted (OP) directory assistance to fully automated speechrecognition (ASR) directory assistance. In the example of FIG. 1, the OPpath uses store and forward (SF) techniques, but other operator-assistedtechniques could be used.

As illustrated in FIG. 1, in response to a caller's dial-up fordirectory assistance, a dialog with the caller conditionally proceeds,continuing with an ASR dialog so long as the recognition is successful.At any step, if the recognition is not successful, the unrecognizedresponses are stored and forwarded to an OP path. This permits the levelof automation to vary according to the particular call.

In addition to conditionally progressing on the basis of ASR success orfailure, the dialog is implemented with “configuration switches”, whichcan be set so that branching out of ASR can be caused. By setting eachswitch, the dialog may be configured at any one of various stages of thedialog. The switches may be set such that a given configuration isimplemented for all calls. Alternatively, the switches can be set sothat any particular caller's dialog can branch from ASR to SF service atany given point in the call. These switches are “software switches” inthe sense that the method of FIG. 1 is computer-implemented and undercontrol of a computer program.

As explained below, a configuration switch may be set to cause a branchto the SF path, even after a particular question in the ASR dialog hasbeen responded to and the response recognized. This permits the serviceprovider to collect and tune the ASR dialog, while continuing tomaintain a satisfactory level of service for callers.

The directory assistance service provider can monitor ASR success rates,which permits a decision to implement full automation, or to advance orretract the level of automation, to be based on success rates. Becausethis step-wise conditional directory assistance process is under programcontrol, the system can monitor its own performance and return to anearlier more successful level of automation if performance falls below athreshold of success.

FIG. 1 illustrates the basic dialog of a method of controlling the levelof directory assistance automation, using configuration switches inaccordance with one aspect of the invention. A fully automated path isdown the center of FIG. 1 through ASR sub-dialogs 1, 2, 3, and 4 and adatabase search.

Each of sub-dialogs 1–4 is associated with an ASR question, in which thecaller is prompted for a response. ASR techniques are used to attempt torecognize the response. The actual speech recognition process can beaccomplished using various techniques and algorithms used today, or tobe developed, in the art of speech recognition.

A number of configuration switches 102, 104, 107, 111 permit the serviceprovider to branch the remainder of the dialog out of ASR to SF. On theSF path, prompts elicit responses from the caller, which are stored andforwarded to an operator. If all switches are set for no automation, theentire dialog is a simple SF process to an operator who queries adatabase. On the other hand, if all switches are set for fullautomation, the responses provided by the caller result in retrieval ofa telephone number from the database. Setting only some of the switchesresults in various intermediate levels of automation. At the same time,regardless of the level at which the dialog is handed off to anoperator, the system continues to collect and attempt to recognizeresponses prior to that point, so that the ASR can be tuned.

As stated above, the configuration switches can be self-monitoring,permitting the directory assistance process to be automaticallyconfigured for all calls or on a per call basis, at any level. However,if desired, the same switches could be set by the service provider,based on performance reports of ASR success rates.

The method illustrated in FIG. 1 begins with a branding and greetingmessage 101, in which the caller is prompted to state the desiredservice (the goal). A first configuration switch 102 can be set so thatthe dialog either branches to a SF path or proceeds down the ASR path.

On the ASR path, a first speech recognition process 103 attempts torecognize the caller's goal. If the attempt fails, the recorded responseis forwarded to an operator. If the attempt is successful, the dialogproceeds through a next configuration switch 104, which again determineswhether the dialog continues along the automated or operator-assistedpath.

It should be understood from FIG. 1 that even if the recognition at step103 is successful, the configuration switch 104 can be set to cause abranch to the operator-assisted path. This might be the case, if successrates for the next question of the dialog were low. Thus, at a number oflevels during the dialog, there are two ways in which a call can becomean operator-assisted call: following a failed voice recognition responseor if a configuration switch is set.

In Step 105, it is determined whether the caller's goal, as recognizedin Step 103, is “reverse directory assistance” (RDA). If so, thedirectory assistance process branches to an RDA process, described belowin connection with FIG. 4. For purposes of this description, it isassumed that RDA is the only goal other than “telephone number”, butother services and branching to processes other than RDA are possible.

In Step 106, the caller is prompted for, and responds with, a city andstate. If the speech recognition fails, the recorded responses to bothQuestions 1 and 2 are forwarded to an operator. If the speechrecognition is successful, a next configuration switch 107 determineswhether the dialog continues along an automated or SF path.

At Step 108, the caller is prompted to state whether the desiredtelephone number is residential. If the speech recognition of theresponse fails, the recorded responses to Questions 1–3 are forwarded toan operator. If the speech recognition is successful, the rest of thedialog depends on whether the answer is “yes” or “no”.

If the answer to Question 3 is “yes” (the number is residential), a nextconfiguration switch 109 determines whether the dialog continues to asub-dialog for residential listings or to the SF path. An automated pathfor residential listings is described below in connection with FIG. 2.Other sub-dialogs, including an operator-assisted dialog could be usedfor residential listings.

Step 108 is optional. The branching of FIG. 1 enables the serviceprovider to provide a different mode of service for residential listingsas opposed to business listings, which tend to be easier to obtain. Italso permits different databases to be searched for the two types oflistings. Other embodiments of the invention are possible, in which nodistinction is made between residential and non-residential listings,and both proceed along the main path of FIG. 1.

If the answer to Question 3 is “no” (the number is not residential), atStep 110, the caller is prompted for the listing name. If the speechrecognition fails, the recorded responses to Questions 2–4 are forwardedto an operator. If the speech recognition succeeds, a next configurationswitch determines whether the dialog continues along the automated pathor branches to the SF path.

Continuing on the automated path, Step 112 is performing a databasesearch for the number. If desired, the database search can be forfrequently requested listings only. The search is typically performed asa single query or “dip”, but various searching techniques may be used.

If the result of the search is a single number, the process continues toa give-out process, described below in connection with FIG. 3. If thesearch results in no listing, a next configuration switch 113 determineswhether the search is to be expanded or whether the dialog branches toSF. If the search results in more than one listing, a configurationswitch 114 determines whether the dialog proceeds to a disambiguationprocess (described below in connection with FIG. 5) or to SF. If theconfiguration switch 114 is set for SF, the operator's workstationdisplay is populated with the candidate listings.

Calls whose responses have been handed off to an operator, either aftera failed attempt at speech recognition or by a switch, are delivered toan operator. The operator then queries the database.

As indicated in Step 115, responses leading to both successful andfailed attempts at speech recognition are collected. These responses arethen used to tune the speech recognition process.

FIG. 2 illustrates an example of a sub-dialog for callers who indicatethat they desired a residential listing in response to Question 3 ofFIG. 1. In Step 201, an appropriate directory is selected. In Step 202,an ASR process prompts the caller for a listing, and attempts torecognize the response. If the attempt fails, the dialog defaults to SF.If the attempt succeeds, a configuration switch 202 determines whetherthe call shall proceed as ASR or branch to SF. If switch 202 is set forASR, Step 204 is performing a database search. The following stepsdepend on the number of listings obtained from the search. If a singlelisting is obtained, the number is given out to the caller, a processthat may be implemented as described below in connection with FIG. 3. Ifno listings are obtained, a configuration switch 205 determines whetherthe search is to be expanded or whether the dialog branches to SF. Ifmore than one listing is obtained, a configuration switch 206 determineswhether the dialog branches to SF or proceeds to a disambiguationprocess. The disambiguation process may be performed in the mannerexplained below in connection with FIG. 5.

FIG. 3 illustrates an example of a sub-dialog that may be used for thegive-out process of FIG. 1. In Step 301, a text to speech (TTS) processis used to give out the desired listing. In Step 302, the caller isprompted to indicate any additional services that may be desired. If nomore services are desired, the call is released. Other options includeautomatic dialing or a new search. These options may be implemented withASR to prompt for, and recognize, the caller's response.

FIG. 4 illustrates an example of a sub-dialog that may be used for thereverse directory assistance process of FIG. 1. A first configurationswitch 401 determines whether a DTMF process (Step 402) or ASR process(Step 403) is to be used to obtain the listing. If the area code (NPA)is satisfactory, the dialog proceeds to a database search in Step 404.Otherwise, Step 403 is repeated. If the search obtains a listing, it isgiven out. If not, the caller is informed and the call is released.

FIG. 5 illustrates an example of a disambiguation process that may beused after Step 114 of FIG. 1 or after Step 206 of FIG. 2. There are anumber of different ASR disambiguation techniques, and configurationswitches may be used to control which is used. Techniques 1 and 2 areappropriate when the number of listings found in a search is small, suchas two or three. Configuration switch 502 determines whether Technique 1or 2 is used. Technique 1 might be: “There are two listings with thatname. Do you want the one on Howard Avenue or the one on ArmeniaStreet?” Technique 2 might be: “There are two listings with that name.For the one on Howard Avenue, say ‘one’. For the one on Armenia Street,say ‘two.’” Similarly, when there are many listings found in a search,the service provider may, using configuration switch 503, choose one ofseveral list-presentation techniques that differ in how the callernavigates the list and indicates his choice. In the example of FIG. 5,switch 503 is used to select between Techniques 3, 4, or 5. With thisuse of configuration switch 503, the service provider can evaluate thedifferent disambiguation techniques.

OTHER EMBODIMENTS

Although the present invention has been described in detail, it shouldbe understood that various changes, substitutions and alterations can bemade hereto without departing from the spirit and scope of the inventionas defined by the appended claims.

1. A method of facilitating a dialog for a caller, the dialog beingswitchable from an automated speech recognition (ASR) path to anoperator-assisted (OP) path, the method comprising: providing a seriesof one or more ASR sub-dialogs, each sub-dialog including a promptrequesting information from the caller and a response from the caller;performing an ASR analysis of each received response, wherein each ASRanalysis may be successful or unsuccessful; after each ASR sub-dialog,branching the dialog to the OP path if the ASR analysis for thatsub-dialog is not successful; and providing a configuration switch aftera particular ASR sub-dialog that can be set to branch the dialog to theOP path for one or more subsequent ASR sub-dialogs even if the ASRanalysis for the caller's response in the particular ASR sub-dialog issuccessful; wherein the configuration switch is controlled based atleast on a success rate of ASR analyses of previously received callerresponses for an ASR sub-dialog that follows the particular ASRsub-dialog in the series of ASR sub-dialogs.
 2. The method of claim 1,wherein the configuration switch is controlled automatically.
 3. Themethod of claim 1, further comprising: forwarding at least one responseto a speech recognition tuning process; and tuning an ASR analysis basedat least on the forwarded responses.
 4. The method of claim 1, whereinthe one or more ASR sub-dialogs include a first sub-dialog prompting thecaller for a location response and applying an ASR analysis to thecaller's location response and a second sub-dialog prompting the callerfor a listing response and applying an ASR analysis to the caller'slisting response.
 5. The method of claim 4, wherein the configurationswitch follows the caller's listing response.
 6. The method of claim 4,wherein the configuration switch follows the caller's location response.7. The method of claim 1, wherein one of the ASR sub-dialogs prompts thecaller to respond whether the listing is for a residence.
 8. A method offacilitating a dialog for a caller, the dialog being switchable from anautomated speech recognition (ASR) path to an operator-assisted (OP)path, the method comprising: facilitating a first ASR sub-dialog with acaller and performing a first ASR analysis of a response received fromthe caller during the first ASR sub-dialog; if the first ASR analysis isunsuccessful, automatically branching the dialog to the OP path;determining whether a configuration switch is set to branch the dialogto the OP path after the first ASR analysis even if the first ASRanalysis is successful; wherein the configuration switch is controlledbased at least on a success rate of ASR analyses of previously receivedcaller responses for a second ASR sub-dialog; if the first ASR analysisis successful, and if the configuration switch is set to branch thedialog to the OP path, branching the dialog to the OP path prior to asecond ASR sub-dialog; and if the first ASR analysis is successful, andif the configuration switch is not set to branch the dialog to the OPpath, proceeding to the second ASR sub-dialog.
 9. The method of claim 8,further comprising: forwarding multiple responses, including theresponse received from the caller during the first ASR sub-dialog, to aspeech recognition tuning process; and tuning the first ASR analysisbased at least on the forwarded responses.
 10. The method of claim 8,wherein the directory assistance dialog includes one or more ASRsub-dialog preceding the first ASR sub-dialog.
 11. The method of claim8, wherein the first ASR sub-dialog includes prompting the caller for alocation response.
 12. The method of claim 8, wherein the first ASRsub-dialog includes prompting the caller for a listing response.
 13. Acomputer-readable medium having computer-executable instructions forfacilitating a dialog for a caller, the dialog being switchable from anautomated speech recognition (ASR) path to an operator-assisted (OP)path, comprising: instructions for facilitating a series of one or moreASR sub-dialogs, each sub-dialog including a prompt requestinginformation from the caller and a response from the caller; instructionsfor performing an ASR analysis of each received response, wherein eachASR analysis may be successful or unsuccessful; instructions forbranching the dialog to the OP path if the ASR analysis for a particularASR sub-dialog is not successful; and instructions for providing aconfiguration switch after a particular ASR sub-dialog that can be setto branch the dialog to the OP path for one or more subsequent ASRsub-dialogs even if the ASR analysis for the caller's response in theparticular ASR sub-dialog is successful; wherein the configurationswitch is controlled based at least on a success rate of ASR analyses ofpreviously received caller responses for an ASR sub-dialog that followsthe particular ASR sub-dialog in the series of ASR sub-dialogs.
 14. Thecomputer-readable medium of claim 13, further comprising instructionsfor: forwarding at least one response to a speech recognition tuningprocess; and tuning an ASR analysis based at least on the forwardedresponses.
 15. The computer-readable medium of claim 13, wherein the oneor more ASR sub-dialogs include a first sub-dialog prompting the callerfor a location response and applying an ASR analysis to the caller'slocation response and a second sub-dialog prompting the caller for alisting response and applying an ASR analysis to the caller's listingresponse.
 16. The computer-readable medium of claim 15, wherein theconfiguration switch follows the caller's listing response.
 17. Thecomputer-readable medium of claim 15, wherein the configuration switchfollows the caller's location response.
 18. A method of facilitating adialog for a caller, the dialog being switchable from an automatedspeech recognition (ASR) path to an operator-assisted (OP) path, themethod comprising: providing a series of one or more ASR sub-dialogs,each sub-dialog including a prompt requesting information from thecaller and a response from the caller; performing an ASR analysis ofeach received response; wherein each ASR analysis may be successful orunsuccessful; after each ASR sub-dialog, branching the dialog to the OPpath if the ASR analysis for that sub-dialog is not successful; andproviding a configuration switch after a particular ASR sub-dialog thatcan be set to branch the dialog to the OP path for one or moresubsequent ASR sub-dialogs independent of the ASR analysis for thecaller's response in the particular ASR sub-dialog; wherein theconfiguration switch is controlled based at least on apreviously-determined success rate of ASR analyses for an ASR sub-dialogthat follows the particular ASR sub-dialog in the series of ASRsub-dialogs.
 19. A method of facilitating a dialog for a caller, thedialog being switchable from an automated speech recognition (ASR) pathto an operator-assisted (OP) path, the method comprising: providing aseries of one or more ASR sub-dialogs, each sub-dialog including anutterance from the caller; performing an ASR analysis of the receivedcaller utterance in a particular ASR sub- dialog; and providing aconfiguration switch after the particular ASR sub-dialog that can be setto branch the dialog to the OP path for one or more subsequent ASRsub-dialogs independent of the ASR analysis; wherein the configurationswitch is controlled based at least on a success rate of ASR analyses ofpreviously received caller utterances for another ASR sub-dialog in theseries of ASR sub-dialogs.